1. Field of the Invention
The present invention relates to cyanoacrylate preparations and, more particularly, to the sterilization of cyanoacrylate preparations for use in medical or surgical procedures and to sterilized cyanoacrylate packages.
2. Brief Description of the Background
It is known to use 2-cyanoacrylate esters for bonding tissue in medical or surgical procedures performed upon the human or animal body. 2-cyanoacrylate esters polymerize rapidly, and often instantaneously, upon contact with tissue or fluid. The cyanoacrylate polymer is thereafter degraded, metabolized and removed from the body.
In order to be used for medical, including surgical, purposes, 2-cyanoacrylate ester preparations must be sterilized.
It is known to sterilize 2-cyanoacrylate preparations by the use of heat or of radiation. Both techniques tend to cause polymerization of the cyanoacrylate monomer, or at least tend to reduce the shelf life. There therefore remains a demand in the market place for sterilized 2-cyanoacrylate adhesive compositions which have a good shelf life.
It is believed that sterile 2-cyanoacrylate preparations now on the market have, in the main, been sterilized by the use of ionizing radiation. Whilst ionizing radiation has, therefore, apparently been perceived as the preferred method of sterilization, there is a substantial capital cost associated with this procedure and it necessitates the careful use of dosimetry procedures. The biological effects of radiation can also create their own problems.
Cyanoacrylate monomer must be packaged in an inert and adequately water-resistant container, since atmospheric moisture causes polymerization. Aluminum containers, and more particularly tubes, are sometimes used for cyanoacrylate sold for industrial or commercial purposes.
Polyolefin has been the material of choice for commercial medical-grade cyanoacrylate. Polyolefin containers however are permeable to atmospheric moisture the ingress of which into the container detrimentally affects the properties and shelf life of the stored cyanoacrylate. As already stated, both heat and ionizing radiation tend to cause or promote polymerization of 2-cyanoacrylate monomer, at least to the extent of reducing shelf life and, accordingly, sterile cyanoacrylate requires a container which will not promote or cause polymerization during the sterilization process. Aluminum has not found favour as a container for sterile cyanoacrylate.